Shell script: remove spaces from file name

shitspace.sh

#!/bin/bash
if [[ $# -eq 0 ]]; then
    echo "Usage: ./shitspace.sh <folder where spacy files located>"
    exit 1
fi

cd $1
for oldname in *
do
  newname=`echo $oldname | sed -e 's/ /_/g'`
  mv "$oldname" "$newname"
done

cd ..